Process of manufacturing ferrochromium.



UNITED STATES PATENT OFFICE.

HANS GOLDSCHMIDT AND OTTO WEIL, 0F ESSEN- ON-THE-RUHR, GERMANY, ASSIG-NORS TOGOLDSCHMIDT THERMIT COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

PROCESS OF MANUFACTURING FERROCHROMIUM.

110 Drawing.

To all whom it may concern and Or'ro WEIL, subjects of the King of Prussia, and residents of Essen-on-the-Ruhr,

in the Province of the Rhine, German Empire, have jointly invented certain new and useful Improvements in Processes of Manufacturing Ferrochromium, of which the following is a specification.

In the specification for our U. S. patent application Serial Number 728,450, filed October 29, 1912 is described a process for increasing the yield of chromium in the aluminothermic production of carbon-free ferrochromium from chrome-iron-ore, such process being based on the observation that in the aluminothermic treatment a much higher percentage of the chromium contained in the chrome-iron-ore is caused to pass into the alloy by the addition of a certainvarying percentage of chromium oxid to the mixture of the chrome-iron-ore and aluminum or other reducin metal and then subjecting this-mixture to the aluminothermic reaction.

By this process the yield of chromium from chrome-iron-ore can be increased by about 15 to 20 per cent.

\Ve have found by experiment that various other metal oxids possess the same property which is inherent in chromic oxid, namely, that of allowingor causing a certain percentage of chromium'which otherwise would not take a part in the reaction to enter into the same reaction when chromeiron-ore is subjected to the aluminothermic process. The oxids of cobalt, nickel, molybdenum, tungsten, and vanadium all possess this property in a high degree. If, for example, to an aluminothermic mixture consistlng of chrome-iron-ore and aluminum a certain proportion of oxid of cobalt is Specification of Letters Patent.

Application filed May 22, 1913. Serial No.,769,179.

Patented Dec. 29, 1914.

added and the mixture is ignited the result mg alloy. which of course also contains cobalt, will show a higher percentage of chromium than would. be obtained without the addition of oxid of cobalt. The other metal oxids above referred to will act in a similar way.

The peculiarly improved capability of reaction hereinbefore described of the'chromium is of very great importance for the production of binary and ternary alloys of chromium with other metals. Owing to the fact that the yield of chromium is considerably increased, these alloys, which are of the greatest importance in steel manufacture, can be produced at a considerably lower price than would be the case if the different metals used, such as chromium and tungsten, had to be prepared first and then alloyed.

What we claim is:

1. The process of manufacturing carbonfree ferro-chromium, which consists in mixingmaterials containing iron and chromium with a metal oxid of the character specified adapted to increase the chromium content of the ultimate product, and subjecting the mixture to the alumino-thermic reaction.

2. The process of manufacturing carbonfree ferro-chromium, which consists in mming chrome-iron-ore with a metal oxid of the character specified adapted to increase the chromium content of the ultimate product, and subjecting the mixture to the alumino-thermic reaction.

In witness whereof we have hereunto set our hands in the presence of two witnesses. 

